NORWALK, Conn. -- Limited New Haven Line train service has been restored through Norwalk, Metro-North announced at about 6:40 p.m. Friday, after more than three hours of disrupted rush-hour service.

Train speeds are restricted on two of the four tracks on the Walk Bridge after work crews were able to close the span, Metro-North said.

Earlier in the afternoon, train traffic had been suspended between South Norwalk and East Norwalk while crews worked to close the bridge, a 118-year-old swing span that crosses the Norwalk River.

The first train moved eastbound at 6:20 p.m. at restricted speed of 15 mph.

Metro-North is warning customers to expect substantial residual delays after the service interruption.

4 p.m. original report:

NORWALK, Conn. -- Metro-North is unable to provide train service in either direction through South Norwalk as of about 3:30 p.m. Friday due to a problem with the Walk Bridge, the railroad said in a statement.

Outbound train service is being provided Friday between Grand Central and Stamford, with delays. There is limited train service to South Norwalk only.

"This was a regular opening for marine traffic on the Norwalk River," a Metro-North spokesman said.

Metro-North was working Friday afternoon to arrange for bus service around the problem area:

Metro-North said it was setting up shuttle bus service between South Norwalk and East Norwalk, where customers can then connect to trains to New Haven.

Inbound train service is being provided between New Haven and East Norwalk. Metro-North is setting up shuttle bus service between East Norwalk and South Norwalk, where customers can then connect to trains to Grand Central.

The 118-year-old bridge is stuck in the open position, the Metro-North spokesman confirmed, adding that the exact reason the bridge is stuck was unclear. It was stuck in the open position on May 29 for several hours after a routine check on the mechanics, disrupting the morning commute.

"Mechanics are unable to close the Walk Bridge near South Norwalk and repair crews are on site working to resolve this issue," Metro-North said in a statement.

Several crews are at the site working on resolving the issue, including the overhead wire experts, signal teams and mechanical crews.

"It is subject to the wear and tear that has gone one for the last 118 years," the spokesman said, and could take several hours to repair.

The WALK Bridge rotates open to allow boats to pass through Norwalk Harbor.

The problem was reported as the Friday afternoon rush hour was beginning.

Riders are advised to listen for announcements at stations for updates on the situation.

Commuters took to Twitter once again to lament the delay to their train service.

Stephen Wood under his twitter handle @CTMQ, said "Hey, at least the weather is nice for the 1000's of people stuck on #MetroNorth AGAIN today. pathetic."

Joe M at twitter handle @Joemanc31 questioned the opening of the bridge. "Why do they even open that bridge in Sono? It's not like tall cruise ships are passing through! #metronorth."

Still others spoke out about delays to their weekend plans and using hashtags like #failroad to express their frustrations.